1. Field
The disclosed embodiments relate to a method for processing a beverage, destined for human or animal consumption, with the aim of increasing the sweetness of said beverage. The method can be used for processing alcoholic beverages and for processing non-alcoholic beverages. The disclosed embodiments method can particularly apply to processing wine. A further aspect of the disclosed embodiments is a sweetener destined to be used for processing a beverage with the aim of increasing its sweetness.
2. Brief Description of Related Developments
Taste-modifying agents of different chemical and biological origins commonly used in the agri-foodstuff industry are well known, particularly for giving organoleptic characteristics to beverages and foodstuffs. For example, aspartame is a sweetening agent of peptide origin used in the agri-foodstuff industry. Proteins, such as thaumatin, can also possess sweetening properties of this kind (Gibbs et al., 1996).
Certain peptides probably of yeast origin (Desportes et al., 2001) and found in champagne-based wines are also cited as possessing organoleptic properties such as bitterness, acidity and umami (beef stock flavour).
However, these peptides often need to be added in large doses to beverages in order to be detected on a sensory level. The term “large dose of peptide”, as used herein, is understood to mean at least 5 g/L.
In the regulatory context of oenological practices, certain processes are allowed in order to improve the organoleptic properties of wines, and one of these is ageing on lees.
During ageing on lees, a great number of biochemical and physical-chemical phenomena take place in the wine, which tend to modify its organoleptic properties.
Ageing white wines on lees is a very old technique used in maturing “grands vins” white wines in vats, particularly those from the Burgundy region. This method of maturing is now used all over the world. The biochemical and physical-chemical phenomena associated with this practice are the results of interactions between the wine, the yeasts and possibly with the wood, and lead to the improvement of the organoleptic qualities and the physical-chemical stability of the white wines stored in this way.
For example, the lees modify the woody flavour of white wines. Particularly, the vanilla flavour is less intense in wines that are fermented and stored in barrels than when they are run off after alcoholic fermentation and/or stored decanted. This phenomenon is due to the reduction of vanillin by the yeasts contained in the lees (Chatonnet et al., 1992). On the other hand, the fermentation and storage in barrels may also increase the toasted flavours, by the production of furanmethanethiol by the lees from the furfural in the heated wood (Tominaga et al., 2000).
Ageing on lees also increases the parietal polysaccharide content of the wines, and particularly the mannoprotein content (Llaubères et al., 1987). The result is a spontaneous improvement of the protein (Ledoux et al., 1992) and tartaric (Moine-Ledoux et al., 1997) stability of the wines. Moreover, the polysaccharides liberated during the ageing on lees can combine with the phenol compounds of the wine and the ellagitanins from the barrel (Chatonnet et al., 1992). This natural clarifying carried out during the batonnage (stirring) of the lees helps stop the colour of white wine changing and also helps stop the wood tannin bitterness developing and prevents the wine from pinking on oxidation.
Moreover, thanks to their reducing power, lees play a key part in reduction-oxidation phenomena. Fornairon et al., 1999, have recently shown their capacity to bind dissolved oxygen. In barrels their presence is absolutely necessary to protect certain fruity aromas from oxidation.
At the same time, lees prevent the oxidative aromas characteristic of defective aromatic ageing from developing (Lavigne-Cruège et al., 1999). Storing wine on lees can lead to the appearance of unpleasant sulphur odours, so that the wine needs decanting rapidly. In fact, as long as the sulphite reductase remains in the yeasts, dry white wines undergoing vinification in large capacity vats cannot be aged on lees, without the risk of reduction defects appearing. But if the lees are temporarily separated from the wine and stored in barrels, they can be reintroduced later when they have lost all their reducing activity. Moreover, their addition at this stage brings about a very marked decrease in the concentration of certain thiols such as methanethiol or ethanethiol. Disulphide bridges exist between the cysteine residues that constitute these mannoproteins (located in the outer walls of the yeast cells) and the SH groups of the thiols, which allow the yeasts to fix the thiols (Lavigne et Dubourdieu, 1996).
The many positive consequences of ageing white wines on lees have led some winemakers to apply this practice to maturing red wines, hoping to obtain organoleptic advantages, since the lees are purported to make wines “fat and well rounded”, that is, to make them sweeter.
In red wines, ageing on lees also helps limit oxidation phenomena while acting, to a certain extent, on the texture of the wines. It has been reported in the literature (Escot et al. 2001) that glycoproteins of parietal origin, released during the autolysis of the yeasts present in the lees, seem to have an action on certain polyphenolic fractions resulting in a decrease in the astringent sensations related to these fractions.
In general, as those skilled in the art are well aware, one of the several effects of ageing red or white wines on lees is an increase in the sweetness of said wines.
However, it is not easy for the practitioner to manage these increases in sweetness. This is because controlling the ageing on lees depends on many factors, such as the duration, the temperature, the frequency of batonnage, the colloid structure of the wine, etc.
Moreover, this technique is costly to implement, and so cannot be envisaged on all wines. Lastly, this technique generally only applies to alcoholic beverages.